班級:碩研機械一甲 姓名:田正雨 學號: M9810213 Micro-EDM of sintered diamond.
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Transcript of 班級:碩研機械一甲 姓名:田正雨 學號: M9810213 Micro-EDM of sintered diamond.
班級:碩研機械一甲姓名:田正雨學號:M9810213
Micro-EDM of sintered diamond
• excellent hardness and very low frictional wear
• machine SD(Sintered diamond) with high precision by conventional methods such as cutting and grinding
Introduction(1/2)
• Since SD contains metal as binder, it is electrically conductive
• Micro-EDM, its ability to machine regardless of the hardness of the workpiece
• four types of SD, composed of 1, 3, 10 and 20 μm diamond particles
Introduction(2/2)
• Panasonic MG-ED72 micro-EDM machine, WEDG, 50μm-diameter cylindrical electrodes(tungsten)
• Binder (cobalt) , approximately 5%
• Tungsten carbide alloy was also tested for comparison
Experiments(1/3)
• Hole machining:
• Discharge capacitance was 100 pF, and the open-circuit voltages were 100, 80, and 60 V
• measured the machining time, the electrode wear, and the side gap
Experiments(2/3)
• Trench machining:
• The size of the trenches : 50 μ m (width) × 4 mm (length) × 30 μm (depth)
• 100v, 3300 pF(rough), 100 pF(medium) and stray capacitance(10pF, finish machining)
• surface roughness at the bottom of the trenches
Experiments(3/3)
• Shape of machined holes:
• There is no significant difference of size and roundness among all holes
• This fact suggests that precision and micro EDM of SD is practical
Results and discussion _ Hole machining(1)
Ø 50μ m, 100 V and 100 pF
• Machining speed:
• 20 μ m at 60 V and 80 V could not be machined :electrode wear was so large
• Machining speed, SD and tungsten carbide alloy : No significant difference
Results and discussion _ Hole machining(2)
Volmetric machining speed
• Machining speed:
• 100V 、 80V, machining speed apparently decreases : debris
• The same phenomenon :3 μ m , BUT, 10 μ m and 20 μ m appears to be constant
Results and discussion _ Hole machining(3)
diamond particle:Debris influence :
• Electrode wear
• The wear ratio:tungsten carbide < SD
• Machining speed:
Electrode wear:
Results and discussion _ Hole machining(4)
• Side gap
• There is no apparent correlation between diamond particle size and side gap
Results and discussion _ Hole machining(5)
• Surface roughness:
discharge capacitance :
the surface roughness :
Results and discussion _ Trench machining(1)
• Observation of machined surface(By SEM)
Results and discussion _ Trench machining(2)
Same craters craters
diamond particles are small:can be removed
diamond particles are largea part of particles
• Round Ø 50 μ m micro holes were proved, 1–20 μ m
• Electrode wear ratio appeared to have a strong correlation with machining speed
• Side gap not have apparent correlation with diamond particle size.
Conclusions(1/2)
• There is no significant difference in machining speed between SD and tungsten carbide
• A surface roughness of approximately 0.13 μ m Ra was achieved for trench machining.
Conclusions(2/2)